Guide wires typically are used, for example, to “thread” bone fragments after a bone fracture and before introduction of an intramedullary pin. The guide wire can be a long, flexible and relatively thin rod with a proximal end at which the guide wire can be gripped and with a distal end that can be advanced through the bone channel or the channels of bone fragments, in order to thread the fragments.
In this activity, it would be advantageous if the location of the distal end of the guide wire were known at any time. It would then be possible to ascertain whether said distal end has been advanced far enough to guarantee sufficient threading.
At present, the proximal end or the whole guide wire is tracked in a tubular bone with the aid of fluoroscopic recordings (e.g., x-ray recordings or the like), wherein the position of the guide wire is visualised using C-arc x-ray equipment and, thus, the position of the distal end can be compared to the bone or bone fragments. The relatively high number of single x-ray recordings or even continuous x-ray recordings needed for this subjects both the patient and the surgeon to high radiation loads.
In medical technology, the use of magnetic field navigation has been proposed for the targeted insertion of cannulae or catheters. Examples of magnetic field navigation are shown in U.S. Pat. Nos. 6,104,944 and 6,783,536 B2. However, magnetic field navigation or similarly functioning types of navigation that navigate or positionally detect hidden instruments inside a body are technically complex and susceptible to faults.
Optical navigation systems are known, for example, from DE 196 39 615 A1, which is incorporated herein by reference in its entirety. However, up until now it has not been deemed possible to positionally determine an instrument section of a flexible instrument lying inside a patient's body by means of an optical navigation and tracking system. This is simply due to the fact that the course of the flexible instrument has not been deemed to be detectable and it has not been possible to expediently arrange an optical reference array on the flexible part or on the tip of the flexible part, since this part is located inside the body structures.